Performance Analysis of FSO DF Relays with Log-Normal Fading Channel

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Ha Duyen Trung
Keyword(s):  
Performance Analysis ◽  
Error Rate ◽  
Communication Systems ◽  
Free Space Optical ◽  
Error Performance ◽  
Relay Nodes ◽  
Decode And Forward ◽  
Log Normal ◽  
Optimal Average ◽  
The Impact

AbstractThis paper studies the bit error performance analysis of decode-and-forward (DF) relays-based free-space optical (FSO) communication systems using avalanche photodiode (APD). The system uses subcarrier intensity binary phase shift keying (BPSK) modulated signals and subjects to scintillation due to optical turbulence. A log-normal random process is considered to model the received signal intensity fluctuation for a clear-air condition (weak atmospheric turbulence) scenario. Mathematical expressions of the average bit error probability and bit error rate (BER) are derived by taking into account the impact of atmospheric loss, thermal-noise and shot-noise limited conditions. It can be inferred from the numerical results that using DF relay nodes can extend the transmission distance and minimize BER performance of FSO system significantly compared with the direct transmission. Moreover, the selection of APD’s gain values is essential to minimize the system’s error rate performance. Therefore, the system could achieve the minimal BER by selecting an optimal average APD gain value appropriately. Moreover, the optimal average gain values of APD significantly depend on various conditions, such as the bit rate, total transmitted power, and the number of relay nodes.

Performance Analysis of Reconfigurable Intelligent Surface in a Dual-Hop DF Relay Empowered Asymmetric RF/FSO Networks

2021 ◽  
Author(s):  
Kehinde O Odeyemi ◽  
Pius A. Owolawi ◽  
Oladayo O. Olakanmi
Keyword(s):  
Performance Analysis ◽  
Closed Form ◽  
Atmospheric Turbulence ◽  
Performance Metrics ◽  
Beam Width ◽  
High Signal ◽  
Free Space Optical ◽  
Decode And Forward ◽  
Pointing Errors ◽  
The Impact

Abstract In this paper, the performance analysis of a reconfigurable intelligent surface (RIS) in a dual-hop decode-and-forward (DF) relay empowered asymmetric radio frequency (RF)/free space optical (FSO) systems is presented. The RIS-assisted RF network is subjected to Nakagami-m distribution while the RIS-assisted FSO networks experience Gamma-Gamma distribution in which both atmospheric turbulence and pointing errors are considered. Thus, the closed-form expressions for the system outage probability and average bit error rate (ABER) are derived with limited number of reflecting elements at RIS-assisted RF network and multiple number of reflecting elements at RIS-assisted FSO network. Further, to obtain more insight about the system characteristic, the asymptotic closed-form expressions are derived at high signal-to-noise ratio (SNR) for the system performance metrics. The results illustrate the impact of the system and channel parameters on the proposed system in terms of atmospheric turbulence, pointing errors under beam width condition, m-fading parameter, and number of reflecting elements. The correctness of the derived analytical expressions is validated via the Monte-Carlo simulations.

On the End-to-End Performance of a Mixed RF-FSO link with a Decode-and-Forward Relay

2019 ◽  
Vol 40 (3) ◽  
pp. 323-332 ◽  
Author(s):  
Himanshu Khanna ◽  
Mona Aggarwal ◽  
Swaran Ahuja
Keyword(s):  
Atmospheric Turbulence ◽  
Error Rate ◽  
Path Loss ◽  
Symbol Error Rate ◽  
Free Space Optical ◽  
Short Term ◽  
Decode And Forward ◽  
Pointing Error ◽  
The Impact

Abstract In this paper, we investigate the performance of a decode-and-forward relayed mixed radio frequency-free space optical (RF-FSO) dual-hop link. The transmitter to receiver link’s first-hop is a RF channel and the second-hop is a FSO channel. The RF link experiences long-term shadowing and short-term multi-path fading effects, while the FSO channel suffers atmospheric turbulence fading, path loss, and pointing error-induced misalignment fading. The performance of the system is analyzed considering the impact of these parameters. We model the RF link by generalized-K fading distribution and the atmospheric turbulence over the FSO link by the gamma–gamma fading. The expressions in closed form for the outage probability, symbol error rate for the system employing $q$-ary PSK modulation schemes, and the channel capacity of the system are derived. The obtained numerical results are also depicted by numerical plots.

Error performance analysis of optical communication over Lognormal-Rician turbulence channel using Gram-Charlier Series

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Maoke Miao ◽  
Xiaofeng Li
Keyword(s):  
Error Rate ◽  
Symbol Error Rate ◽  
High Signal ◽  
Free Space Optical ◽  
Error Performance ◽  
Maximum Ratio Combining ◽  
Rate Analysis ◽  
De Algorithm ◽  
Shift Keying ◽  
The Impact

Abstract In this paper, the symbol-error rate (SER) performance of a coherent free-space optical (FSO) communication system in lognormal-Rician turbulence channel is analyzed using the generalized Gram-Charlier (GCC) series. We proposed the differential evolution (DE) algorithm to solve the parameters in GCC efficiently. It is shown that highly accurate closed-form SER expressions are obtained for M-ary phase-shift keying (MPSK) and M-ary quadrature amplitude modulation (MQAM) schemes with maximum ratio combining (MRC) technique. The asymptotic error rate analysis is presented to reveal the performance behavior in the high signal-to-noise (SNR) regime. The effects of imperfect phase noise compensation on the error rate performance are also studied, and it is found that the impact of phase compensation error can be small enough with loop SNR ρ c more than seven.

Performance Analysis of Amplify-and-Forward Relaying FSO/SC-QAM Systems over Weak Turbulence Channels and Pointing Error Impairments

2017 ◽  
Vol 39 (1) ◽  
Author(s):  
Ha Duyen Trung
Keyword(s):  
Atmospheric Turbulence ◽  
Communication Systems ◽  
Symbol Error Rate ◽  
Aperture Size ◽  
Free Space Optical ◽  
Amplify And Forward ◽  
Pointing Error ◽  
Log Normal ◽  
The Impact ◽  
Af Relaying

AbstractIn this paper, the end-to-end performance of free-space optical (FSO) communication system combining with Amplify-and-Forward (AF)-assisted or fixed-gain relaying technology using subcarrier quadrature amplitude modulation (SC-QAM) over weak atmospheric turbulence channels modeled by log-normal distribution with pointing error impairments is studied. More specifically, unlike previous studies on AF relaying FSO communication systems without pointing error effects; the pointing error effect is studied by taking into account the influence of beamwidth, aperture size and jitter variance. In addition, a combination of these models to analyze the combined effect of atmospheric turbulence and pointing error to AF relaying FSO/SC-QAM systems is used. Finally, an analytical expression is derived to evaluate the average symbol error rate (ASER) performance of such systems. The numerical results show that the impact of pointing error on the performance of AF relaying FSO/SC-QAM systems and how we use proper values of aperture size and beamwidth to improve the performance of such systems. Some analytical results are confirmed by Monte-Carlo simulations.

scholarly journals Energy Optimization of a Laser-Powered Hovering-UAV Relay in Optical Wireless Backhaul

2021 ◽  
Author(s):  
Muhammad Salman Bashir ◽  
Mohamed-Slim Alouini
Keyword(s):  
Quality Of Service ◽  
Communication Systems ◽  
Low Cost ◽  
Base Stations ◽  
Achievable Rate ◽  
Optical Wireless ◽  
Free Space Optical ◽  
Decode And Forward ◽  
Wireless Backhaul

<div>Due to their flexibility and low cost deployment, unmanned aerial vehicles (UAV) will most likely act as base stations and backhaul relays in the next generation of wireless communication systems. However, these UAVs---in the untethered mode---can only operate for a finite time due to limited energy they carry in their batteries. In free-space optical communications, one solution is to transport both the data and the energy from the source to the UAV through the laser beam---a concept known as <i>simultaneous lightwave information and power transfer</i> (SLIPT). In this study, we have analyzed the SLIPT scheme for laser-powered decode-and-forward UAV relays in an optical wireless backhaul. The major goal of this study is to optimally allocate the received beam energy between the decoding circuit, the transmitting circuit and the rotor block of the relay in order to maximize a quality-of-service metric such as maximum achievable rate, outage or error probabilities. As expected, we note that the optimal power allocation depends heavily on the source-relay and relay-destination channel conditions. In the final part of this study, we have maximized the operational time of the UAV relay given that the maximum achievable rate stays above a certain threshold in order to meet a minimum quality-of-service requirement.</div>

Free Space Optical Communication System under Different Weather Conditions

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohammad Yawar Wani ◽  
Hitesh Pathak ◽  
Karamjit Kaur ◽  
Anil Kumar
Keyword(s):  
Attenuation Coefficient ◽  
Optical Communication ◽  
Free Space ◽  
Communication Systems ◽  
High Speed ◽  
Free Space Optical Communication ◽  
Free Space Optical ◽  
Wide Range ◽  
Space Optical Communication ◽  
The Impact

AbstractFree space optical communication systems (FSO’s) have surfaced as admired means of communication in the past few years. High speed of operation, low bandwidth requirements and system reliability are the major factors responsible for their wide range of applications. These communication systems use air as a medium of transmission. Since there is no component like fiber or cable, but air is only medium, the variations in atmospheric conditions play a vital role in performance of these networks. The reason behind is that the conditions like presence of humidity, haze, snowfall, rain, dust or smoke changes the attenuation coefficient of medium. The raised attenuation levels results in increased losses and need to be carefully monitored. The present work analyzes the influence of rain on the performance of FSO network in terms of quality of transmission. The paper discusses the impact of rainfall on attenuation coefficient of air. Then impact of this attenuation on network transmission is presented in terms of BER and Q-factor. In order to demonstrate the impact, BER and Q-value is calculated for 10 Gbps FSO link for clear weather and rainfall conditions.

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